Resource types are not the same · wit-bindgen

Stream: wit-bindgen

Topic: Resource types are not the same

Maxim Schuwalow (Jan 16 2025 at 10:45):

I'm trying to wrap a component that implments wasi:http/incoming-handler into a different api. The way I'm trying to accomplish this is by having two different components that will be composed with it.

Exports the wasi:http/types interface + some extensions. This will be composed with (2) and (3) and has otherwise no imports (except other wasi interfaces)
The wrapped component. This imports wasi:http/types and exports wasi:http/incoming-handler.
A component providing the new api. This imports wasi:http/types, wasi:http/incoming-handler, the extensions from (1) and exports the new api.

Problem is that when I try composing the wasm, it errors with

❯ wac plug adapter.wasm --plug types.wasm -o adapter-plugged.wasm
error: encoding produced a component that failed validation

Caused by:
    type mismatch for import `wasi:http/incoming-handler@0.2.3`
    type mismatch in instance export `incoming-request`
    resource types are not the same (ResourceId { globally_unique_id: 2, contextually_unique_id: 8 } vs. ResourceId { globally_unique_id: 2, contextually_unique_id: 57 }) (at offset 0x4e0399)

Can someone help me make sense of this error?

Wits looks as follows:
Component 1:

package poc:types;

interface extensions {
    use wasi:http/types@0.2.3.{method, scheme, status-code, incoming-request, response-outparam};

    type fields = list<tuple<string, list<u8>>>;

    type body = list<u8>;

    record body-and-trailers {
        body: body,
        trailers: option<fields>
    }

    record request {
        method: method,
        path-with-query: string,
        scheme: scheme,
        authority: string,
        headers: fields,
        body-and-trailers: option<body-and-trailers>
    }

    record response {
        status: status-code,
        body: option<body-and-trailers>
    }

    resource response-outparam-proxy {
        constructor();

        new-outparam: func() -> response-outparam;
        get-response: func() -> response;
    }

    new-wasi-http-request: func(request: request) -> incoming-request;
}

world api {
    export wasi:http/types@0.2.3;
    export extensions

Component 2:

package poc:handler;

world api {
  import wasi:http/types@0.2.3;
  export wasi:http/incoming-handler@0.2.3;
}

Component 3:

package poc:adapter;

interface adapted-api {
    use poc:types/extensions.{request, response};

    handle: func(request: request) -> response;
}

world api {
    import wasi:http/incoming-handler@0.2.3;
    import wasi:http/types@0.2.3;
    import poc:types/extensions;

    export adapted-api;
}

Thank you

Last updated: Jan 24 2025 at 00:11 UTC